When I read Task #4, my first thought for a mashup post was "DeMotivational Poster".
You've probably seen them around the net. These are take-offs of the standard "Motivational Posters" using all types of photos with a punch line attached.
One of the benefits of this being a popular mashup is that there are lots of sites that lead you through the steps of doing your own.
I had two main difficulties. The first was getting the photo to save and then upload. Luckily, Bighugelabs (Which is the Flickr site that does motivational posters) has lots of options and i finally stumbled though by posting with the photo's URL.
The second problem was inspiration. It's hard to come up with something clever and funny on command. I finally went with a photo that I had spotted on my earlier search through "Martial Arts" and snatched a clever tidbit from Wikiquote.
The only flaw remaining is that I can't figure out how to select the location of posting the poster. I tried to put the poster about marriage (The one that I did) at the end of this post. But, for some reason, it keeps being sent to the top of the post.
Minor detail. All things considered, it came out pretty well.